Persons located in a forward position toward the dashboard, in particular children, are exposed during the operation of a motor vehicle fitted with an airbag to the risk of suffering injury due to the force of inflation of the airbag in the event of an accident. Modern control systems for personal protection have sought to disconnect the airbag in such situations or to inflate it with less force, to prevent the risk of injury to an occupant. Contactless, optical sensors are preferably used to detect the position of the occupant in the vehicle.
A known device for contactless detection of an object or a person in the passenger compartment of a vehicle is known, for example, from U.S. Pat. No. 5,585,625 or EP 0 669 227. In these examples, the seat of the vehicle is exposed to radiation from a number of light diodes. Beams reflected by the vehicle seat or a person or an object on the vehicle seat are detected by a photodetector field.
The light source used in the optical detection system is preferably a laser, which allows precise scanning due to its monochrome radiation. Laser diodes, and in particular semiconductor laser diodes, are usually used as transmitters.
In order to prevent the laser imposing a sustained energy load on persons in the passenger compartment, the laser is pulsed. But even in this operating mode, the health of the occupant should under no circumstances be impaired as a result of the laser light pulses emitted.